Volume 48, Issue 9 pp. 2442-2449
Research Article

Activin A induces cell proliferation of fibroblast-like synoviocytes in rheumatoid arthritis

Fumie Ota

Fumie Ota

Gunma University School of Medicine, Maebashi, Japan

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Akito Maeshima

Akito Maeshima

Gunma University School of Medicine, Maebashi, Japan

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Shin Yamashita

Shin Yamashita

Gunma University School of Medicine, Maebashi, Japan

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Hidekazu Ikeuchi

Hidekazu Ikeuchi

Gunma University School of Medicine, Maebashi, Japan

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Yoriaki Kaneko

Yoriaki Kaneko

Gunma University School of Medicine, Maebashi, Japan

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Takashi Kuroiwa

Takashi Kuroiwa

Gunma University School of Medicine, Maebashi, Japan

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Keiju Hiromura

Keiju Hiromura

Gunma University School of Medicine, Maebashi, Japan

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Kazue Ueki

Kazue Ueki

Gunma University School of Medicine, Maebashi, Japan

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Itaru Kojima

Itaru Kojima

Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan

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Yoshihisa Nojima

Corresponding Author

Yoshihisa Nojima

Gunma University School of Medicine, Maebashi, Japan

Third Department of Internal Medicine, Gunma University School of Medicine, 3-39-15 Showa, Maebashi, Gunma 371-8511, JapanSearch for more papers by this author
First published: 11 September 2003
Citations: 76

Abstract

Objective

To investigate the expression of activin A and its receptors in rheumatoid arthritis (RA) synovial tissues, and to determine the effect of activin A on cultured fibroblast-like synoviocytes (FLS).

Methods

The localization of activin A and activin type II receptor (ARII) in synovial tissues of RA patients was analyzed by immunohistochemistry. The expression of activin A and activin receptors in human cultured FLS was examined by reverse transcriptase–polymerase chain reaction and Western blotting. Enzyme-linked immunosorbent assay was used to measure activin A in culture supernatants. The cell growth of FLS was determined by 3H-thymidine incorporation and MTT assay.

Results

Immunohistochemical analysis confirmed the up-regulation of activin A in rheumatoid synovium as compared with osteoarthritis or normal joint tissues. CD68+ macrophage-lineage cells and vimentin-positive FLS were identified as activin-producing cells in rheumatoid synovium. Both cell types also expressed ARII. The expression of activin A and ARII on cultured FLS was confirmed at the protein and messenger RNA levels. Interleukin-1β (IL-1β), tumor necrosis factor α, and transforming growth factor β activated FLS to secrete activin A. Recombinant activin A accelerated the proliferation of FLS, while follistatin, an endogenous activin antagonist, partially inhibited FLS proliferation induced by IL-1β.

Conclusion

These results suggest that activin A acts as a growth factor of FLS in RA.

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